Computers, printers, facsimile machines and similar types of electronic equipment include electronic circuits and components formed in or mounted on a main circuit board. In a personal computer the microprocessor chip and the random access memory chips, for example, are mounted on the main circuit "mother" board. In a laser printer, the main circuit board is typically the formatter board. The formatter board includes the microprocessor and related memory chips that control the functions of the printer. Other circuits and components are often mounted on circuit cards that are plugged into the main circuit board. Modem cards, network cards, infrared connectivity cards and other option cards are examples of circuit cards that might be used in a computer or printer.
Option cards are usually plugged into the main circuit board with some type of socket connector. Edge connectors in which electrical contacts along the edge of the card are plugged into a mating female socket mounted on the main circuit board are the most common card connectors in computers. Usually, a cover and screws must be removed and reinstalled to access the female socket on the main circuit board to install the option card. It is desirable to eliminate or at least minimize the need for tools and screws during customer installation of circuit cards. In some printers, the circuit card edge contacts are plugged into sockets at the back of the frame tray in which the formatter board is fastened. Circuit cards used in these printers must be large enough to reach the sockets even if this size is not necessary to accommodate the circuitry and electronic components on the card. The formatter board or ribbon cable from the formatter board must also extend to the connector at the back of the frame. It would be advantageous to mount the circuit card and make electrical contact to the formatter or main circuit board independent of the size of the frame.